Method of producing gasoline by alkylation and reforming



May 23, 1950 A. J. ABRAMs Er Ax.

METHOD oF PRoDucING GAsoLmE BY ALKYLATION REFORMING 2 Sheets-Sheet lFiled July 19, 1945 CARL J. HUA/l1, da.

.lNVENTOR May 23, 195o A. J. ABRAMS ETAL 2,509,028

METHOD 0F' PRODUCING GASOLINE BY ALKYLATION REFORMING 2 Sheets-Sheet 2lFiled July 19, 1945 INVENTOR ,com

Patented May 23, 1950 Applicationrluly 19, 1945,;seriairuwoaasa I2 (cl.26o-683,4)

7 This `aplolication. isa continuation-irl-part; f.

our -copendina application Serial No. 431.95816, filed April..l2,.1,942,` andl now. abandoned..

This; inventionrelates .toithe catalytic, marin;r

lfacture of. high.octane.,gaso1ine, The inyention is directedparticularly. toa.- method'of catalytically reforming a, relativelynarrow boiling, iso.- parafn fraction. suchasforzexample. aztypicalparaftinic` alkylate, so. as-: to; :gia/e. a complete-.gaso: line ofhigh l.octane-.value The`r alkylation of.` isoparariic;` hydrocarbonswith, olenic, hydrocarbons` for v theproduction-of isoparafns .of `highoctane valueizboiling in;l the gasoline range is now awell;.established: fart. Henetofore, various catalystshavebeenrprfoposed for this reaction, such. as. sulfuric ,acid,..'phosphoricracid, Y aluminum .chloride etc. t has morearecently. beendiscovered. U. S.'Patent;No. 2,2613730Mthat aklyla-tion `reactions offther .above type .may be carried.. out in. a highly desirable manner byusing a catalyst consisting .essentially fofhydrogen fluoride;

f Sin-ce -aikylation processes,. as usually;l con.-v d-ueted, effectpredominantly the conderzusation` of one particular isoparan.-With-oneparticular olefin, Ythe resulting. alkylategaso1ine,..-.althcugh lo-fhigh octane value; is. composed-.predominantlyof-1 isomers of 'ionef paraflnic'- hydrocarbon Therefore, the alkylateisofmelativelylnarrow--boiling range which is liess than-that of 4acomplete gasoli-ne Vorf-at leastysuch allay-latel doesl not 1- haver-auniform Adistribution -o'f hydrocarbons across the desired gasolineboilingrange'. Asis -Wellknown, gasolineslshouldl be ofY adequate`boiling'range and have their constituents rather` uniformly -dis-V`catalytic re-a'rrangem'ent vor reformingk ofisoparafins'y Vsuch' asalkylate hydrocarbons; boiling inthe gasolinera-nge to yield' acompos-itegaso- 'line which boils over lan entire gasoline rangea-ndlwhichpossesses substantially as high an :antiknock 'value as a blendedAalkylate gasoline6 ln accordance with that invention, therefrislshown,

for example,V a process of reformingjisoparafns Y inv the lpresence ofhydrogen 'uoridefto yield? a hydrocarbon mixture wlhichboils over yanlentire cartons.thatlowenboilinafhndrarbons. be formait'frognthatharaestoclaas.; .well` er boilinahrdrooarbons. Tha present .inveritialis 20hydrogen .Euer-ide.. A morespecina object-,1s

to catalyticallysrefotm suchfnarrow boiiinglfzfra:tionsbyfa.noyelemethodtoeobtain a completegaas: .olinefot highoetanevafluefarid properManor131.1125. suretanddistillationrfchanacteristicsh Accordingly,.an\embodirnent orourlinvention is-canrietirout-.by-z feeding. `,an .entirevai-kylation.:reaction mixture.' .containing -hydro-uoric acidicatfalyst into-.a trantionatlng unitfand .the isoparafns.arelreiormedaby further: contact 30 with the hydrogen fluoride catalystunder condi@ tions i, whichl maintain;v materialarof@gasc'lineelooil-fingrange,arl-iclz lfligher.:in liquidaformwhilejliglnter material;v 'includ-ingmydrogen .uoririaA waporizes. Thesetapers ofilighter material are lecleto'r'a com denser, .and-thecondensate thfereirornisalilowe tributed in ordertoinsure properCarburation 1 l v-toseparate intotwo-Alayersttvizfy-.anupperohyxitrocar/bon'- layeranti-1aliowenhydrogen.uor;ide layer. Thehycirocarlbon` layer-1 is:composedprimarilymf light isoparai-ns, e. tg. isobutane rana.isopehtane, which are 'le-ft overV from -theifcharge :stoek;...i`present therein,k and which are: produced dur-.ing there-formingstep;l'The normally liquid hytlro'- carbone or thereactionfmixtureand somehydro gen fluoridearelwitladraWn-fromthe: fractionating unit in-liquidform and'- ltreatediti-1a manner l'aterAdescr-ibedf.

For a. -f-ullerur-nierstandingof .the invention, reference will befmadetor-the aocompanyin-gttraw- 'ings-f- W-hereinu-Fiigure-lshowslldiagrammatiicaily .59 'av prefer-red.Y apparatus l setup" forconducting; our

process; Vand '-lFigure y-2iy 'is a graph showing' the ability @Pourreita-mingy process to: produce-)new productsofvastiystliiferent-distillationichanactera gasoline range. It*isf-especially interesting. to 'isti'csf-from -narrow boil-ing.ractioJrIs-.cty \.gaso1ihe note that this processis :capableofefectingsuch 55 boiling-r .isopa-rains. acompletencorrversionforfactionotthehyciroe VInf-operatiori-riet'err-ing .lnoWL-.toi Fifgureffil--a suitableisoparaflinic charging stock is fed continuously through lines I and 2onto a feed plate 3, in the middle of column 4. Column 4 may perform thedual function of a fractionation and a reforming chamber, and issuitably constructed for effecting proper contact of isoparaiins and HF.Lower boiling liquid isoparaftlns are used as a reflux for column 4, andare introduced by line 5 to distributor 6. In order to afford stillgreater exibility of operation in column 4, provision is made forintroducing liquid HF through line 'I to column 4 at a point below wherereaction mixture is fed in. This serves to increase the quantity of HFin contact with the high boiling hydrocarbons and, therefore, the extentof reforming-all other factors being constant. Provision for returningadditional liquid HF to the bottom section of the column can be made byrecycling a part of the HF from gravity separator 8.

`Conditions within the column 4 are maintained so that gasoline boilinghydrocarbons and higher boiling hydrocarbons remain liquid and are drawnoi at the bottom of the column through pipe I'I. Lighter hydrocarbonmaterial and a portion of the hydrogen fluoride vaporize and theresulting vapors pass upwardly through the column counter-current to thedown-flowing liquid. These vapors are led from the top of column 4through line 9 to condenser I0. The condensate from condenser IU is ledthrough line II and line I2 to gravity separator I3, and a part also maybe recycyed through line Il and line I4 to reaction Vessel I5,containing high-speed mixer I5a. The condensate in separator I3separates into two layers, namely, an upper hydrocarbon layer and alower hydrogen fluoride layer. The upper hydrocarbon layer in separatorI3 passes through line 5 to column 4 as reflux, and the lower hydrogenfluoride layer in separator I3 passes through line I to the bottom ofcolumn 4, both as explained hereinabove. If desired, however, any partof either of the two layers in separator I3 might be sent to reactor I5by suitable pipes (not shown) Additional hydrogen fluoride as needed maybe introduced to the system through line I6.

The crude reformed product is withdrawn from the bottom of column 4through line I'I and passed into gravity separator 8. Here the productseparates'from accompanying liquid HF to form two layers. The productlayer is taken through line I8 to fractionating and/or refiningequipment (not shown). The HF in separator 8 is removed through line I9and passed thereby back to reaction vessel I5, or it is diverted fromline I9 through line 2li and sent either through line 2I back to thebottom of column 4 or sent through line 22 to an HF purification system(not shown) and the purified HF is returned to the system. Thispurification system may comprise merely a distillation column forvaporizing HF.

, The liquid product withdrawn from the bottom of column 4 and sent tothe fractionation system may be fractionated in order to cut out a.desired gasoline fraction, and the light and heavy ends obtained in thisfractionation, may be led either to reactor I5, along with the lowboiling isoparans (isobutane and isopentane) taken over-head in column4, for further treatment in the presence of HF, or may be withdrawnpermanently from the reaction cycle. It is usually desirable, however,to return the heavy ends to the reaction vessel I5 along with lowboiling isoparamns and HF, in order to increase the yield ofgasoline-boiling hydrocarbons. This may be done by means of line 23.These heavy ends behave like olens in reacting with light isopar-Reaction mixture withdrawn from reactor I5 is sent to column 4 via lines25 and 2.

Therefore, it may be seen that the isopara'lnic material of gasolineboiling range which is sent to column 4 may be derived from severalsources. Thus, the isoparailinic charge stock fed through line I may beisoparafns of gasoline boiling range derived from any source, and, ofcourse, might be the reaction mixture of an HF alkylation process. Inthis latter case, such HF alkylation process may be conducted in aseparate reactor or it may be conducted in the reactor I5 along with theother reactions mentioned above as being carried out in reactor I5. Inany of these embodiments. ail, any part or none of the materialsmentioned above as being recycled to reactor I5 may be so recycled.

Column 4, as explained hereinabove, is preferably both a reforming andfractionating unit and is of appropriate construction therefor. Thus,for example, the section of the column above the feed plate 3 maycomprise a series of bubble-cap trays which serve to strip the lowboiling hydro'- carbons from the higher boiling hydrocarbons; while thesection below this feed piate may be packed with an inert material, as,for example, carborundum, with occasional bubble-cap trays being used ascollectors and re-distributors of liquids. It is to be understood thatthe single column 4 could be replaced by two columns, one of whichperforms the function of the upper section of column while the otherperforms the function of the lower section of column 4. Moreover, ifdesired, the alkylation reactor might be made a section of the column.

The higher boiling hydrocarbons which travel downwardly through thelower section of the column in the presence of the liquid HF arereformed to an extent which is dependent upon: (1) contact time, (2)temperature, (3) ratio of low boiling (usually isobutane) to highboiling hydrocarbons in the mixture, and (4) amount of HF present. Thesefour variables may be adjusted to give substantially any gasoline rangematerial desired. It is a simple matter to substantially completelyalter the hydrocarbons of the narrow boiling range charging stock togive a mixture of hydrocarbons which form a complete high octanegasoline of proper distillation and vapor pressure characteristics.

The advantages and improvements effected lby a reforming operation ofthe type brought about in fractionating-reforming column 4 of ourapparatus are best shown, perhaps, by the graph in Figure 2. In thisgraph per cent volume of gasoline distilled is plotted againstdistillation temperature, and three curves are given, viz., curves A, B,and C. By referring to this graph, it will be seen that a heptanealkylate, produced by alkylating isobutane with propylene andrepresented by curve A, is concentrated in a rather narrow boiling rangebetween and 100 C. On the other hand, curve B shows that when thisheptane alkylate is reformed (in the absence of added hydrocarbons), amixture of hydrocarbons isobtained which distills rather uniformlyasoegoas 5. overfaneentire gasoline ranges Itfalso-=shouldl1be notedythat the-'reformed 'productis essentiallya totally` dierent product fromthe original 1 alkylate: Thus, only about'lO to 12%y ofthe-re formedproduct .boils within the boil-ing rangelof the entire alkylatefraction. Moreover, even the ft() 12% of hydrocarbons remaininginthissame range-needinotnecessarily` be of the same structureL as theoriginal alkylate hydrocarbons. CurveV Cfshows that when addedisobutaneis present, modification of the final productl isobtainedlwhichstill yields a gasoline boiling -rather uniformlyover theentire gasolinerange but havlngf'a higher concentration of hydrocarbons .in the:-middleportion of the gasoline. Thisconcentration of hydrocarbons in themiddlefporA tion-of the gasoline can be varied. to .almost any extentbythe. present invention which removes the-light hydrocarbon gases fromvthel alkylate prior to-separation of HFfrom the` alkylate. This eieotfof.the isobutane apparently" is vone--ofmass action:l

The temperature for reformingisoparans in the presence of. HF may bebetween, sayabout -eland about A200," C., dependingV upon the desiredoperating. pressureand the reactivity. of fthe isoparailins.. Providingsuicient contact timein th'ecolumn... to attain. thedesired amount ofre-V forming, presents no.-.particular problem.V The ee'ctobtained byvarying the amount vof light gaseous. hydrocarbons and also.-hydrofluoric acid has .been describedabove, as wellfasmeans forattainingssame. Therefore, it should be apparent thatuathe. variables ofthe processare subject .tov completelccntrol, and maybeeasily correlatedvto givethe. desired result.

An outstanding feature of our. process resides in thefact that light.gaseous ends. are removed from .the `reaction mixture. .in thepresen'ce.of an exeessoof HF, and bymeansof'I-IF, and before. the.=remainder ofthe hydrocarbons are. separated. froml As a result, we are. able toexert.a greater influence on thev reforming stepandregu.- latertoa ner degreethe characteristics. of the products. Thus, in most cases, it isdesirablev to have the isoparaiilnic charging lstock freeoflow boiling.Aisoparaiilns, including even. thesmall arnountzproduced duringreforming, before .separating-.theproductfrom-HF. This, of course,issaccomplishedeasily by the presentprocess.

Itsis perhapsv well to note at this. time that the distillation of twoirnnriiscible` liquids.such,as a mixtureofliquid HF. and. liquidhydrocarbons, fol! lcwsa steam distillation principle. accordingtothe-equation Wnrweightof HF in overheadvapors Wnd=weight ofhydrocarbon in overheadV vapors Bnn=vaporpressure of HF at temperature tPnc=vapor pressure oi' hydrocarbon. at tempera-f turet.

Marr-:molecular weight ofA HF in, vapor phase at temperature t M`1r c,=.molecular weight of hydrocarbon vapor at temperaturet.

However," HF is highly associatedin the Avapor phase-and its apparentmolecular weight varies fromabout 77 at -i0 C. to about: 25 at 130: C.Itf will' beseen, therefore, that War/WHC: decreaseswith increasingtemperature..A According@ lyfit-afollows that; a more. completeseparation.- yof Hiifrom; -sobutaneby distillation .canV bei obtained 6.at.higherwtemperatures;k Therefore?. iii desired the operation in.column 4 maybe conxluctedifrat temperatures which Y are substantiallyabove i. the boiling fpoint of hydrogen uorideat atmospheric pressure(which-is 19.4 0.); both-because of fthe above reasonv andalso-because-a higher A reforming temperatureis thereby maintained:

The amount-of HF'chargedto the columnein excess of that vleavingthecolumnas overhead 1 the distillation step involved in our reformingoperation is` eliminated; However, it -is to noted that to 99% acid lisanalkylating agent of higher specificity and may be used The processdescribediabove is also described in our co-pendingapplication SerialNo.. 43935162 filed April 12', 1942 and now abandoned.

1. The processof producing.v a relatively wide boiling mixture of vhighquality gasolineboiling hydrocarbons from a relativelyy narrow boilingalkylate produced byr anwalkylatijon stepjfzherein light t iso-parafiinsare reactedvjwith, lolefins under alkylating conditions inthepresencewof acatar. lyst consisting essentially ofghydrogeniluoride,which comprises` passingv alkylation reaction mixture comprisingrelatively` narrow.v boiling, alkylate gasoline.. normally gaseoushydrooarv bons, and hydrogen fluoride to a fractionating; reformingzone,A maintaining said zone under such conditions that normally gaseoushydrocarbons are vaporized while gasolineboilinghydrocarbons and higher,hydrocarbons remain inv the liquid state, continuing. tol contact saidalkylate with said hydrogen fluoride `in said.frao vtionating-reforrnng. zone; until substantial ref forming ofthe alkylateis effected,l fractionating off the normally gaseous .hydrocarbons fromsaid' zone duringthe reformingoperationas ayapbr mixture withhydrogenl-uoride, withdrawing, a. mixtureY of reformed gasoline boilinghydrocarf bons,v .higher hydrocarbons. and` hydrogen fluoride inliquidphase from near.v the bottom of said.

zone, condensing said vapor.v mixture .and sepaf rating the condensateinto ahydrocarbonlayerand ahydrogen uoride layenpassing thehy;ndrocarbon layer. to. the top ofsaid fractionation zone as reux andpassing the hydrogen fluoride layer to said. Zone.. at a point neartbebottom thereof, separatingI said. withdrawnliquid mix:- ture into ahydrocarbon.. phase and ahydrogen fluoride.. phase,v fractionating. saidhydrocarbon phase. to produce a. gasoline. boiling4 fraction-:and afraction of` higher boiling, liquidhydrocarbons, and returningthislatter fraction to the alkylar; tionstep.,.

2., The rprocess. of claim 1.whereintne contact between the. hydrogenuoride vand the ,normally liquid. hydrocarbons in, saidfractionatingg'e-r forming.. zone is .suicientto produce. ay .completegasoline. of proper distillation andvapor. prese. sure characteristics.`n t 3. The.Vv process ofproducing highqualitygasb: line from arelatively narrow boiling; alkylate produced by? analkylation,stepwherein light..,isoe lla-radins arefreacted withlolensrunder; aalliyltf lng conditions inthe presence of a catalyst consistingessentially of hydrogen fluoride, which comprises passing alkylationreaction mixture comprising relatively narrow boiling alkylate gasoline,normally gaseous hydrocarbons, and hydrogen fluoride to afractionating-reforming zone, maintaining said zone under suchconditions that normally gaseous hydrocarbons are vaporized whilegasoline boiling hydrocarbons and higher hydrocarbons remain in theliquid state, continuing to contact said alkylate with said hydrogenfluoride in said fractionatingreforming zone until sufficient reformingof the alkylate is effectedvto give a complete gasoline of properdistillation and vapor pressure characteristics, fractionating oif thenormally gaseous hydrocarbons from said zone during the reformingoperation as a vapor mixture with hydrogen fluoride, withdrawingreformed gasoline and higher hydrocarbons in liquid phase from saidzone, fractionating vsaid withdrawn gasoline and higher hydrocarbons togive a gasoline fraction and a, fraction of higher liquid hydrocarbons,and returning said fraction of higher hydrocarbons to said allrylationstep for the production of further quantities of gasoline boilinghydrocarbons.

4. The process of producing a relatively wide boiling mixture of highquality gasoline boiling hydrocarbons from a relatively narrow boilingalkylate produced by an alkylation step wherein light isoparaiilns arereacted with oleflns under alkylating conditions in the presence of acatalyst consisting essentially of hydrogen fluoride, which comprisespassing allrylation reaction mixture comprising relatively narrowboiling alkylate gasoline, normally gaseous hydrocarbons, and hydrogenfluoride to a fractionating-reforming zone, maintaining said zone undersuch conditions that normally gaseous hydrocarbons are vaporized whilegasoline boiling hydrocarbons and higher hydrocarbons remain in thelid-uid state, continuing to contact said alkylate with said hydrogenfluoride in said fractionating-reforming zone until substantialreforming of the alkylate is effected, fractionating oi the normallygaseous hydrocarbons from said zone during the reforming operation as avapor mixture with hydrogen fluoride, withdrawing reformed gasolineboiling hydrocarbons and higher hydrocarbons in liquid phase from saidzone,

bons to said alkylation step for the production of further quantities ofgasoline boiling hydrocarbons.

5. The process of manufacturing high quality gasoline from a relativelynarrow boiling alkylate produced by reacting light isoparafns with olensin the presence of a catalyst consisting essentially of hydrogenfluoride, which comprises passing alkylation reaction mixture comprisingrelatively narrow boiling alkylate gasoline, normally gaseoushydrocarbons, and hydrogen fluoride to a fractionating-reforming Zone,maintaining said zone under such conditions that normally gaseoushydrocarbons are vaporiaed While gasoline boiling hydrocarbons andhigher hydrocarbons remain in the liquid state, continuing to contactsaid alkylate with said hydrogen fluoride in saidfractionating-reforming zone until suflicient reforming of the alkylateis effected to give a complete high quality gasoline of` properdistillation and vapor pressure characteristics, fractionating oi thenormally gaseous hydrocarbons from said zone during the reformingoperation as a vapor mixture with hydrogen fluoride, and withdrawingsaid high quality gasoline and higher hydrocarbons in liquid phase fromsaid zone.

6. The process of producing a relatively wide boiling mixture of highquality gasoline boiling hydrocarbons from a relatively narrow boilingalkylate produced by reacting light isoparaiiins with oleiins in thepresence of a catalyst consisting essentially of hydrogen fluoride,which comprises passing alkylation reaction mixture comprisingrelatively narrow boiling alkylate gasoline, normally gaseoushydrocarbons, and hydrogen fluoride to a fractionating-reforming zone,

maintaining said zone under such conditions that normally gaseoushydrocarbons are vaporized while gasoline boiling hydrocarbons andhigher hydrocarbons remain in the liquid state, con-v tinuing to'contact said alkylate with said hydrogen fluoride in saidfractionating-reforming zone until substantial reforming of the alkylateis effected, fractionating off the normally gaseous hydrocarbons fromsaid zone during the reforming operation as a vapor mixture withhydrogen fluoride, withdrawing gasoline boiling hydrocarbons andhigherhydrocarbons in liquid phase from near the bottom of said zone.

7. The process of claim 6, wherein the distilling off of the vapormixture of hydrogen fluoride andv normally gaseous hydrocarbons from thefractionation zone is effected by distilling at a tem-v perature whichis substantially above the atmospheric boiling point of hydrogenfluoride so as to obtain a relatively low ratio of hydrogen fluoride tohydrocarbons in said vapor mixture.

8. The process of producing a relatively wide boiling mixture of highquality gasoline boiling hydrocarbons from a relatively narrow boilingalkylate produced by reacting light isoparains with oleflns in thepresence of a catalyst con" sisting essentially of hydrogen iiuoride,which comprises passing alkylation reaction mixture comprisingrelatively narrow boiling alkylate gasoline, normally gaseoushydrocarbons, and hydrogen fluoride to a fractionating-reforming zone,maintaining said zone under such conditions that normally gaseoushydrocarbons are vaporized while gasoline boiling hydrocarbons andhigher hydrocarbons remain in the liquid state, continuing to contactsaid alkylate with said hydrogen fluoride in said fractionating-re`forming zone until substantial reforming of the alkylate is effected,fractionating off the normally gaseous hydrocarbons from said zoneduring the reforming operation as a vapor mixture with hydrogenfluoride, withdrawing reformed gasoline boiling hydrocarbons, heavierhydrocarbons and hydrogen fluoride in liquid phase from said zone, andrecycling said normally gaseous hydrocarbons and said heavierhydrocarbons removed from said fractionating-reforming zone to saidalkylation step.

9. The process of producing reformed gasoline,v

of relatively wide boiling range from a relatively narrow boilingfraction of gasoline boiling iso-. para'ins which comprises feeding therelatively narrow boiling fraction of isoparaiiins and a catalystconsisting of hydrouoric acid as the eiective catalytic agent to afractionating-reforming zone, maintaining said zone under suchconditions that normally gaseous hydrocarbons are vaporized whilegasoline boiling hydrocarbons and higher hydrocarbons remain in theliquid state., contacting said isoparains with said hydrogen uoride insaid fractionating-reforming zone until suicient reforming ofisoparaflins is effected to give complete gasoline of properdistillation and vapor pressure characteristics, fractionating offnormally gaseous hydrocarbons from said zone during the reformingoperation as a vapor mixture with hydrogen fluoride, condensing andreturning at least a portion of the vaporized hydrogen fluoride to saidzone, and withdrawing said complete reformed gasoline and higher boilinghydrocarbons in liquid phase from said zone.

10. The process of producing reformed gasoline of relatively wideboiling range from a relatively narrow boiling fraction of gasolineboiling isoparains which comprises feeding the relatively narrow boilingfraction of isoparaillns and a catalyst consisting of hydrofluoric acidas the effective catalytic agent to a fractionating-reforming zone,maintaining said zone under such conditions that; normally gaseoushydrocarbons are vaporized while gasoline boiling hydrocarbons andhigher hydrocarbons remain in the liquid state, contacting saidisoparains with said hydrogen fluoride in said fractionating-reformingzone until substantial reforming of the isoparailn is effected,fractionating off normally gaseous hydrocarbons from said zone duringthe reforming operation as a vapor mixture with hydrogen fluoride,'condensing and returning at least a portion of the vaporized hydrogenfluoride to said zone, and withdrawing said reformed gasoline boilinghydrocarbons and higher hydrocarbons in liquid phase from said zone.

11. The process of producing a relatively wide boiling mixture of highquality gasoline boiling hydrocarbons from a relatively narrow boilingfraction of gasoline boiling isoparafns which comprises feeding saidisoparalns and hydrogen fluoride of alkylation strength to afractionatingreforming zone, maintaining said zone under such conditionsthat normally gaseous hydrocarbons are vaporized while gasoline boilinghydrocarbons and higher hydrocarbons remain in the liquid state,contacting said isopara'ins with hydrogen fluoride in said zone untilsubstantial reforming of the isoparains is effected, fractionating offlnormally gaseous hydrocarbons from said zone during the reformingoperation as a Vapor mixture with hydrogen fluoride, withdrawingreformed gasoline boiling hydrocarbons and higher hydrocarbons in liquidphase from said zone, fractionating said withdrawn liquid hydrocarbonsto give a. gasoline boiling fraction and a fraction of higher liquidhydrocarbons, passing said higher hydrocarbons along with lightisoparafllns to an alkylation zone, reacting said higher hydrocarbonsand said light isoparafllns in said alkylation zone in the presence ofhydrogen fluoride of alkylation strength to produce gasoline boilingisoparaifns, and passing these gasoline boiling isoparafhns to saidfractionating-reforming zone.

12. The process of producing a relatively wide boiling mixture of highquality gasoline boiling hydrocarbons from a relatively narrow boilingfraction of gasoline boiling isoparailins which comprises feeding saidisoparains and hydrogen fluoride of alkylation strength to afractionatingreforming zone, maintaining said zone under such conditionsthat normally gaseous hydrocarbons are vaporized while gasoline boilinghydrocarbons and higher hydrocarbons remain in the liquid state,contacting said isoparaflins with hydrogen fluoride in said zone untilsubstantial reforming of the isoparaflins is effected, fractionating offnormally gaseous hydrocarbons from said zone during the reformingoperation as a vapor mixture with hydrogen fluoride, withdrawing aliquid mixture of reformed gasoline boiling hydrocarbons, higherhydrocarbons and hydrogen fluoride from said zone, condensing said vapormixture and separating the condensate into a hydrocarbon layer andhydrogen fluoride layer, returning the hydrocarbon layer to the top ofsaid fractionating-reforming zone as reflux and passing the hydrogenfluoride layer to said zone at a point near the bottom thereof,separating said withdrawn liquid mixture into a hydrocarbon phase and ahydrogen fluoride phase, fractionating said hydrocarbon phase to producea gasoline boiling fraction and a fraction of higher boilinghydrocarbons, passing said Ihigher hydrocarbons along with isobutane toan alkylation zone, reacting said higher hydrocarbons and said isobutanein said alkylation zone in the presence of hydrogen fluoride ofalkylation strength to produce gasoline boiling isoparaflins, andpassing these gasoline boiling isoparaftins to saidfractionating-reforming zone.

ARMAND J. ABRAMS. CARL S. KUHN, JR.

REFERENCES CITED UNITED STATES PATENTS Name Date Arnold July 10, 1945Number

1. THE PROCESS OF PRODUCING A RELATIVELY WIDE BOILING MIXTURE OF HIGHQUALITY GASOLINE BOILING HYDROCARBONS FROM A RELATIVELY NARROW BOILINGALKYLATE PRODUCED BY AN ALKYLATION STEP WHEREIN LIGHT ISO-PARAFFINS AREREACTED WITH OLEFINS UNDER ALKYLATING CONDITIONS IN THE PRESENCE OF ACATALYST CONSISTING ESSENTIALLY OF HYDROGEN FLUORIDE, WHICH COMPRISESPASSING ALKYLATION REACTION MIXTURE COMPRISING RELATIVELY NARROW BOILINGALKYLATE GASOLINE, NORMALLY GASEOUS HYDROCARBONS, AND HYDROGEN FLUORIDETO A FRACTIONATINGREFORMING ZONE, MANTAINING SAID ZONE UNDER SUCHCONDITIONS THAT NORMALLY GASEOUS HYDROCARBONS ARE VAPORIZED WHILEGASOLINE BOILING HYDROCARBONS AND HIGHER HYDROCARBONS REMAIN IN THELIQUID STATE, CONTINUING TO CONTACT SAID ALKYLATE WITH SAID HYDROGENFLUORIDE IN SAID FRACTIONATING-REFORMING ZONE UNTIL SUBSTANTIALREFORMING OF THE ALKYLATE IS EFFECTED, FRACTIONATING OFF THE NORMALLYGASEOUS HYDROCARBONS FROM SAID ZONE DURING THE REFORMING OPERATION AS AVAPOR MIXTURE WITH HYDROGEN FLUORIDE, WITHDRAWING A MIXTURE OF REFORMEDGASOLINE BOILING HYDROCARBONS, HIGHER HYDROCARBONS AND HYDROGEN FLUORIDEIN LIQUID PHASE FROM NEAR THE BOTTOM OF SAID ZONE, CONDENSING SAID VAPORMIXTURE AND SEPARATING THE CONDENSATE INTO A HYDROCARBON LAYER AND AHYDROGEN FLUORIDE LAYER, PASSING THE HYDROCARBON LAYER TO THE TOP OFSAID FRACTIONATION ZONE AS REFLUX AND PASSING THE HYDROGEN FLUORIDELAYER TO SAID ZONE AT A POINT NEAR THE BOTTOM THEREOF, SEPARATING SAIDWITHDRAWN LIQUID MIXTURE INTO A HYDROCARBON PHASE AND A HYDROGENFLUORIDE PHASE, FRACTIONATING SAID HYDROCARBON PHASE TO PRODUCE AGASOLINE BOILING FRACTION AND A FRACTION OF HIGHER BOILING LIQUIDHYDROCARBONS AND RETURNING THIS LATTER FRACTION TO THE ALKYLATION STEP.